SECTION 4
MAINTENANCE
PREVENTIVE MAINTENANCE
CAUTION
Turn off power before removing or replacing parts.
General Information
The Type 544 is o stable instrument and will provide many
hours of trouble-free operation. However, to mointain meas
urement accuracy, a visual inspection and a calibration check
should be made after each 500 hours of operation or every
six months if used intermittently. The calibration procedures
include steps for checking the operation of various circuits.
Minor troubles not apparent during regular operation will
often be revealed during calibration. Major troubles in the
instrument arc often isolated or eliminated by recalibrating
the instrument.
Visual Inspection
The Type 544 should be inspected occasionally for such
defects os broken connections, broken or damagod ceramic
strips, improperly seated tubes or transistors, and heat dam
aged parts.
The remedy for most visible defects is obvious; however,
particular care must be taken if heat damoged parts are de
lected. Overheating is usually only a symptom of trouble.
For this reason, it is essential to determine the oelual cause
of overheating before the heat-damaged parts are replaced,
otherwise, the damage may be repeated.
Cleaning
The Typo 544 must bo cleaned as often as operating con
ditions require. Accumulations of dirt in the instrument can
cause overheating and component breakdown. Dirt on the
components acts as an insulating blanket (preventing efficient
heat dissipation) and provides conducting paths for elec
tricity. Dirt in the air filter chokes the flow of cooling air
and leads to excessive operating temperature.
Air Filter. The air filter should be visually chocked every few
weeks and cleaned if dirty. More frequent inspections and
cleaning arc required under severe operating conditions. To
clean the filter, wash it out as you would a plastic sponge.
Rinse the filler, and let it dry. Coat the dry filter with fresh
"Filter-Koto'' (Tektronix Part Number 006-580) or "Handi-
Kolcr," (These products are available from the local repre
sentative of the Research Products Corporation, and from
some air-conditioner suppliers.) Let the filter dry thoroughly
before reinstalling.
Exterior. Loose dust accumulating on the outside of the Type
544 can be removed with a cloth or small paint brush. The
paint brush is particularly useful for dislodging dust on and
around the front-panel controls. Stubborn dirt con be re
moved with a soft cloth dampened in a mild solution of
water and detergent. Abrasive cleaners should not be used.
Cleon the face of the ert with a soft, lint-free cloth damp
ened with denatured alcohol.
Interior. Although the air entering the Type 544 is filtered,
some dust will eventually penetrate into the interior of the
instrument. This dust should be removed occasionally due to
its conductivity under high humidity conditions. The best way
to clean the interior of the equipment is to first carefully
vacuum all accessible areas and then blow away the re
maining dust with dry low-pressure compressed air. Avoid
the use of high-velocity air which might damage some of
the components. Remove stubborn dirt with a soft paint brush
or o cloth dampened with a mild water and detergent
solution.
Pay special attention to the high-voltage circuits, including
parts inside the high-voltage shield. Arcing in the high-volt
age circuits due to dust or other causes may produce false
sweep triggering resulting in on unstable ert display.
Lubrication
The fan motor bearings should be lubricated evory three
or four months with a few drops of light machine oil (see Fig.
4-1). Failure to lubricate the bearings periodically can cause
the fan to slow down or slop.
Lubrication Points
4-1
Fig. 4-1. Fan motor lubrkotion points.
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